Thread stabilizer for sewing machines



June 10, 1941. J KARLE 2,245,479

THREAD STABILIZER FOR SEWING MACHINES Filed Oct. 24, 1939 n W a cohn BKarla %N@w /WSLW Patented June 10, 1941 MACHINE John D. Karle, RosellePark, N. .L, assignor to The Singer Manufacturing Company, Elizabeth, N.J a corporation of New Jersey Application October 24, 1939, Serial No.300,910

12 Claims.

This invention relates to thread-stabilizers or thread-drags for sewingmachines, through which the thread runs from the supply spool to theusual sewing machine tension device. When the machine is operated athigh speed without a thread-stabilizer, the thread Whips, jerks anddances around in a most uncertain and bizarre manner, interfering withthe smooth and even formation of stitches.

This uneven flow of the thread from the supply often results in snarlsand kinks and even causes the thread to break. The oflice of athreadstabilizer is to exert a light drag upon the thread between thesupply spool stand and the regular sewing machine tension device, sothat the thread will runto the tension device smoothly and insubstantially a straight line, without a quiver.

The present invention has for an object to provide an efficientthread-stabilizer of simple construction and easy threadingcharacteristics through which the thread from the supply will run freelyand smoothly without danger of kinking or snarling,

Another object of the invention is to provide a thread-stabilizerreadily applicable to a conventional sewing machine in substitution forthe conventional spool-pin thereof Still further, the invention has foran object the provision of a thread-stabilizer which is free of thedanger of grooving by wear of the thread passing therethrough.

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations, and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingof a preferred embodiment of the invention, from which the severalfeatures of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

Of the accompanying drawing, Fig. 1 is a side elevation of athread-stabilizer embodying the invention with the Weight in its loweror working position. Fig. 2 is a similar View with the Weight raised tothreading position. Fig. 3 is a top plan view of the device; Fig. 4 is asection on the line 44, Fig. 3. Fig. 5 is a section on the line 55, Fig.3. Fig. 6 is a bottom perspective view of the Weight and uppertension-disk contained thereby. Fig. 7 is a vertical section similar toFig, 4 but showing a modified form of construction for confining theupper tension disk in the weight, and Fig. 8 is a sectional view throughthe thread-inlet guide.

- portion 8 of the post I,

In the preferred form of the invention there is a center post I thelower end of which is tapered at 2 to fit the conventionaltapered-spoolpin socket of a sewing machine bracket-arm 3 which maybeformer concentrically of thesocket 2 with a ring wall 4' rising a shortdistance from the top surface of the bracket-arm 3 proper. Thecenter'post I is preferably formed with a collar 5'- below which and upon thepost I the lower tension disk '6- is loosely confinedby the collar 1having a drive fit upon the cylindrical The tension disk 6 is freetoturn on the post I but is confined against vertical movement thereon.Near the top of the post I is a cross-pin 9 which is driven through atransverse hole in the post.

Sli'olable vertically upon the post I is the hemispherical weig-ht I0having a peripheral skirtportion H and a-recessed under face containingthe upper tension disk l2 which is free to turn relatively to the WeightIll and is also loose on the post I above the collar 5. The spring ringi3 peripherally underhangs and confines the upper tension disk It in therecess containing it. This ring. lifts the tension disk l2 when theWeight is raised to threading position, Fig. 2.

When the weight is in lowered position, the

cross-pin. 9 lies in the key-slot I4 cut externally in the dome of theWeight and locks the Weight against turning on the post. At the bottomof the key-slot M the weight is under-cut to form a circular clearanceway M for the cross-pin 9, permitting the weight tobe turned on thepostwhen lifted to threading positionFig. 2 in which position it' restsuntil the weight is reversely turned to aline the key-slot M. with. thecross-pin 9 whereupon the weight drops to its operative position, Figs.1, 3 and 4.

Thev skirt portion II of the weight is formed with a thread inlet holel5 and a thread outlet slot l6 both of which are of generous size.

When the weight is raised to threading position, the lower edge of theskirt H thereof is at a. level between the separated tension disk 6 andi2 and serves as a guide to direct the thread sidewise of itself betweensuch disks. As both tension disks are free to turn on the post I, thereis no danger that the thread passing therebetween will wear groovestherein and ruin theeffectiveness thereof. The ring wall 4 serves toprevent displacement of the emerging run of the thread from the outletslot and further serves to prevent the entering run of thread fromwhipping or looping itself under the skirt and around the center post I.The ring wall 4 is, however,

not essential to the invention in its broader aspects. The center post Iand parts carried thereby may be substituted for the conventionalspoolpin of any sewing machine using thread running from a supplyspool-stand.

In the modification of the invention shown in Fig. 7, the uppertension-disk I2 is peripherally underhung and confined by the spun-overflange [1 formed on the under face of and integral with thehemispherical weight. In this form of the invention also, the tensiondisk I2 is free to turn relative to the weight which confines it,

The skirt diameter of the present weight is about 1 /2 inches and it weihs about two ounces.

These figures are not at all critical, however, and may be widelydeparted from within the scope of the invention. The device is intendedto apply only a light drag upon the thread, a fraction of that appliedby the conventional sewing machine thread-tension device to which thethread runs from the thread-stabilizer.

Having thus set forth the nature of the invention, what I claim hereinis:

1. A sewing machine thread-stabilizer comprising, a supporting post, aweight vertically movable on said post from a lowered to an elevatedposition and having a peripherally depending skirt, and a pair ofthread-tension disks on said post within and above the level of thelower edge of said skirt, said skirt having threadinlet andthread-outlet passageways therethrough.

2. A sewing machine thread-stabilizer comprising, a supporting post, aweight vertically movable on said post from a lowered to an elevatedposition and having a peripherally depending skirt, and thread-tensionmeans on said post within said skirt, said skirt having threadinlet andthread-outlet passageways therethrough, and means to temporarily retainsaid weight in an elevated position exposing the tension means forthreading.

3. A sewing machine thread-stabilizer comprising, a supporting post, aweight vertically movable on said post from a lowered to an elevatedposition and having a peripherally depending skirt, and thread-tensionmeans on said post within said skirt, said skirt having thread-inlet andthread-outlet passageways therethrough, and means to prevent turning ofthe weight upon said post when in lowered position.

4. A sewing machine thread-stabilizer comprising, a supporting post, ahemispherical weight slidable on said post and having a circularperipheral skirt and a recessed under face within said skirt, an uppertension disk disposed in said recessed under face and surrounding saidpost, means carried by said weight and underlapping said uppertension-disk to confine the latter in said recessed under face, and alower tension disk loose on said post.

5. A sewing machine thread-stabilizer comprising, a supporting post, ahemispherical weight slidable on said post and having a circularperipheral skirt and a recessed under face within said skirt, an uppertension disk loosely confined in said recessed under face andsurrounding said post, a lower tension disk loose on said post, and

means to temporarily retain said weight in an elevated position with theplane of the lower edge of said skirt higher than said lower tensiondisk.

6. A sewing machine thread-stabilizer comprising, a supporting post, aherispherical weight slidable on said post and having a circularperipheral skirt and a recessed under face within said skirt, an uppertension disk disposed in said recessed under face and surrounding saidpost, disk confining means carried by said weight and underlapping saidupper tension-disk, a lower tension disk loose on said post, and ashoulder on said post overlying the lower tension disk. 7. A sewingmachine thread-stabilizer comprising, a vertical center post, a weightslidable vertically on said post, interengaging means on said weight andpost to confine said weight against turning on said post when saidweight is in lowered position, said weight having a circularly recessedunder face, a circular tension disk in said recess, circular meansperipherally underhanging said tension disk and fixed to said weight forloosely confining said tension disk in said recess, and a second tensiondisk rotatable on said post below said first mentioned tension disk.

8. A sewing machine thread-stabilizer comprising, a supporting post, aweight vertically movable on said post from a lowered to an elevatedposition and having a peripherally depending skirt, thread-tension meanson said post within said skirt, said skirt having threadinlet andthread-outlet passageways therethrough, and a base supporting said postand formed with a ring wall surrounding the skirtportion of said weightand extending above the level of the lower edge of said skirt-portionwhen said weight is in lowered position.

9.. A sewing machine thread-stabilizer comprising, a supporting post, apair of tension disks on said post, a weight on said post bearing downupon said tension disks, means to key said weight against turning onsaid post, and means on said weight to guide a thread to said disks.

10. A sewing machine thread-stabilizer comprising, a weight having arecess and a skirt around said recess, weight-operated thread-tensionmeans in said recess, said skirt having thread-guiding means therein, acenter post supporting said weight, and means to key said weight againstturning on said center post.

11. A sewing machine thread-stabilizer comprising, a supporting post, aweight slidable on said post and having a recess in its under face, athread-tension disk disposed in said recess, disk confining meanscarried by said weight and underlapping said disk, and a companionthreadtension disk on said post.

12. A sewing machine thread-stabilizer comprising, a support, a Weightslidable relative to said support and having a recess in its under face,a thread-tension disk disposed in said recess, disk confining meanscarried by said weight and underlapping said disk, and a companionthread-tension disk carried by said support independent of said weight.

JOHN D. KARLE.

